There are ways to make RoD less cancerous thing, but by the end you will argue “is it still Ritual of Doom?” and ask " Do i want another Cooldown? when warlocks are already very cooldown reliant?".
1 - Reduce the Cooldown from 60minutes to something like 10 minutes: There is absolute no reason to have a Damage cooldown have an 1 hour CD, An 10 minute cooldown is restrictive enough to only be used once per raid fight, and just a couple of times in a dungeon.
2 - Make it Reset on raid wipes: because not having one of your damage abilities for multiple pull is awful [just imagine doing a raid pull without infernal or tyrant].
3 - Remove the “Sacrifice a Friend” and the Ritual requirement of 5 players: Make it something like “loose 50% of your health” when you cast the ritual or something that don’t require your friends to eventually hate you because you are making pulls take 5 times as long and already wiped quite a number of times, Thal’kiel is right you shouldn’t need to have help to summon stuff.
4 - Adjust the duration of enslavement to take in account the 10 minutes cooldown: you can even keep him as a 10 minutes duration, but force the warlock to re-enslave it once or twice across the 10 minutes: this introduces some level of multi-tasking and skill.
Now, i hate the spell, and think it would be much better if they just deleted it even with those changes.